Afdcal 500 mg and reddish/brownish urine

My mother was diagnosed with kidney stone in the year 2019 but since no pain existed, no medication was suggested. Since May 21,she is experiencing some joint/bone pains in her arms and hence yesterday i.e. on 24/06/2021,our family doctor prescribed tablet AFDCAL-500 mg.She took half of the tablet today before lunch.however,she is saying that since evening ,her urine is not the regular one in colour.it's neither completely red or brown.the urine is reddish/brownish in colour accompanied with no pain nowhere. Before taking the tablet,the urine colour was absolutely normal. Also,in the evening ,she has taken the remaining half of the dose of that tablet. Doctor,I request you to kindly advise me- 1.If this is a serious issue or it is related to AFDCAL-500 Mg tablet intake? 2.Should she continue to take the tablet tomorrow? 3.Is this colour of urine related to something else? P.s.: Our family doctor is on leave tomorrow and hence we won't be able to consult anyone till Saturday